How to Repair a Block Wall With Mortar

Block walls are constructed with mortar, which is sometimes actually a form of concrete, a mixture of cement and fine sand. Other blocks are joined with premixed mortar, a powder comprised of sand and lime or cement. Both types of masonry binder are wet with water to form a mud-like paste and spread around the blocks. The mortar dries and the blocks are held in place. However mortar, like block, is porous and can deteriorate over time. If blocks become loose on a wall, you can make the repair with mortar.

Cold chisel
Hammer
Gallon jug
Premixed mortar
Bucket
Paddle mixer
Trowel
Portland cement and masonry sand (optional)

Instructions

- 1
  Remove the loose block by chipping out the old mortar joint with a cold chisel and a hammer. Pull the block out of the space and set nearby on the floor.
- 2
  Even out the emptied space on the block wall using the cold chisel and hammer.
- 3
  Fill a gallon jug with water and pour premixed mortar in a bucket. Pour water onto the mortar in small increments and mix with a paddle mixer, until the mortar is like pancake batter.
- 4
  Scoop some of the wet mortar out of the bucket with a trowel and spread over the bottom of the empty space on the block wall.
- 5
  Set the block into the mortar, then fill the gaps around the block with more mortar using the trowel. Scrape away excess mortar, throw it back into the bucket and mix it back into the wet mortar.
- 6
  Repeat the process of chipping out other loose blocks, then refitting each block back into the empty space and fill the gaps with mortar. Wait 24 hours for the mortar to harden once the repairs have been made.

How to Fill Holes in a Cinder Block Wall

How to Install Glass Block Windows in Siding

Wall Repairs